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Abstract:

A wireless communications device includes multiple switchable antenna
elements that may be used to improve interfacing of the wireless
communications device with other devices, such as for interfacing of an
RFID-equipped mobile communications device with other RFID devices (e.g.,
to better ensure power delivery to and/or communication with such other
RFID devices) and/or may be used to characterize various aspects of the
environment around the wireless communications device, such as for
proximity-based functionality.

Claims:

1. A wireless communications device comprising: a housing; an RF
transceiver disposed in the housing; a plurality of antennas coupled to
the transceiver and distributed with respect to the housing; and
processing circuitry disposed in the housing and coupled to the RF
transceiver, the processing circuitry configured to cause the RF
transceiver to transmit an RF reference signal, to determine at least one
characteristic of the RF reference signal reflected back from each of the
plurality of antennas, to store the at least one determined
characteristic, and to process the at least one determined characteristic
in order to select at least one antenna of the plurality of antennas
based on the at least one determined characteristic.

2. A device according to claim 1, wherein the processing circuitry is
configured to select a plurality of antennas based on the at least one
characteristic of the reflected signal from each of the plurality of
antennas and to selectively couple the plurality of selected antennas to
the transceiver.

3. A device according to claim 2, further comprising a programmable
switching device coupled to the plurality of antennas and to the
processing circuitry, wherein the processing circuitry is configured to
selectively couple the plurality of selected antennas to the transceiver
via the programmable switching device.

4. A device according to claim 3, wherein the processing circuitry is
configured to selectively couple the plurality of selected antennas to
the transceiver in parallel via the programmable switching device.

5. A device according to claim 1, further comprising a controllable
impedance coupled to the plurality of antennas and to the processing
circuitry, wherein the processing circuitry is configured to selectively
control impedance between the RF transceiver and at least one antenna.

6. A device according to claim 1, wherein the at least one characteristic
includes at least one of: amplitude; phase; dispersion; waveform shape;
or distortion.

7. A method of providing RF communication using a wireless communications
device having an RF transceiver and a plurality of antennas coupled to
the RF transceiver, the method comprising: at the wireless communications
device, transmitting an RF reference signal; determining at least one
characteristic of the RF reference signal reflected back from each of the
plurality of antennas; storing the at least one determined
characteristic; and processing the at least one determined characteristic
in order to select at least one antenna of the plurality of antennas
based on the at least one determined characteristic.

8. A method according to claim 7, wherein processing the at least one
determined characteristic in order to select at least one antenna of the
plurality of antennas based on the at least one determined characteristic
comprises: selecting a plurality of antennas based on the at least one
characteristic of the reflected signal from each of the plurality of
antennas; and selectively coupling the plurality of selected antennas to
the transceiver.

9. A method according to claim 8, wherein selectively coupling the
plurality of selected antennas to the transceiver comprises: selectively
coupling the plurality of selected antennas to the transceiver via a
programmable switching device.

10. A method according to claim 9, wherein selectively coupling the
plurality of selected antennas to the transceiver via a programmable
switching device comprises: selectively coupling the plurality of
selected antennas to the transceiver in parallel via the programmable
switching device.

11. A method according to claim 7, further comprising a controllable
impedance coupled to the plurality of antennas and to the processing
circuitry, wherein the processing circuitry is configured to selectively
control impedance between the RF transceiver and at least one antenna.

12. A method according to claim 7, wherein the at least one
characteristic includes at least one of: amplitude; phase; dispersion;
waveform shape; or distortion.

13. A wireless communications device comprising: a housing; an RF
transceiver disposed in the housing; a plurality of antennas coupled to
the transceiver and distributed with respect to the housing; and
processing circuitry disposed in the housing and coupled to the RF
transceiver and configured to cause the RF transceiver to transmit an RF
reference signal, to determine at least one characteristic of the RF
reference signal reflected back from each of the plurality of antennas,
to store the at least one determined characteristic, and to process the
at least one determined characteristic in order to control at least one
function of the device.

14. A device according to claim 13, wherein the at least one
characteristic includes at least one of: amplitude; phase; dispersion;
waveform shape; or distortion.

15. A device according to claim 13, wherein the at least one function
includes at least one of: selecting at least one antenna to couple to a
transceiver; selecting at least one antenna to decouple from a
transceiver; or coupling multiple antennas to form a larger effective
antenna.

16. A device according to claim 13, wherein the processing the at least
one determined characteristic in order to control at least one function
comprises: characterizing at least one aspect of the environment around
the device based on the at least one determined characteristic; and
controlling at least one function of the device based on the at least one
aspect.

17. A device according to claim 16, wherein the at least one aspect
includes at least one of: the presence or absence of an object; the
distance of an object from the device; the location of an object relative
to the device; movement of an object relative to the device; orientation
of an object relative to the device; a disposition of the device; or a
time-of-flight measurement of an object to the device.

18. A device according to claim 17, wherein the object includes a body
part.

19. A device according to claim 13, wherein the at least one function
includes activating a feature of the device based on such
characterization.

20. A device according to claim 19, wherein the feature is activated upon
detecting that an object is approaching the device but before the object
contacts the device.

21. A device according to claim 13, wherein the at least one function
includes: controlling an application running in the device based on such
characterization.

22. A method of controlling at least one function of a wireless
communications device providing RF communication using a wireless device
having a plurality of antennas, the method comprising: at the wireless
communications device, transmitting an RF reference signal; determining
at least one characteristic of the RF reference signal reflected back
from each of the plurality of antennas; storing the at least one
determined characteristic; and processing the at least one determined
characteristic in order to control at least one function of the device.

23. A method according to claim 22, wherein the at least one
characteristic includes at least one of: amplitude; phase; dispersion;
waveform shape; or distortion.

24. A method according to claim 22, wherein the at least one function
includes at least one of: selecting at least one antenna to couple to a
transceiver; selecting at least one antenna to decouple from a
transceiver; or coupling multiple antennas to form a larger effective
antenna.

25. A method according to claim 22, wherein the processing the at least
one determined characteristic in order to control at least one function
comprises: characterizing at least one aspect of the environment around
the device based on the at least one determined characteristic; and
controlling at least one function of the device based on the at least one
aspect.

26. A method according to claim 25, wherein the at least one aspect
includes at least one of: the presence or absence of an object; the
distance of an object from the device; the location of an object relative
to the device; movement of an object relative to the device; orientation
of an object relative to the device; a disposition of the device; or a
time-of-flight measurement of an object to the device.

27. A method according to claim 26, wherein the object includes a body
part.

28. A method according to claim 22, wherein the at least one function
includes activating a feature of the device based on such
characterization.

29. A method according to claim 28, wherein the feature is activated upon
detecting that an object is approaching the device but before the object
contacts the device.

30. A method according to claim 22, wherein the at least one function
includes: controlling an application running in the device based on such
characterization.

Description:

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Patent
Application No. 61/491,380 filed May 31, 2011, which is hereby
incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to antenna elements for a wireless
communications device.

BACKGROUND ART

[0003] Mobile communications devices communicate wirelessly with various
types of devices, such as base stations, satellites and other wireless
devices, using any of a number of wireless protocols using
electromagnetic waves as RF signals. In some mobile devices, the RF
signal is at ISM-band frequencies, between about 2.400 GHz and about
2.483 GHz (used for IEEE 802.11 Wi-Fi and Bluetooth). In other mobile
devices, the RF signal is transmitted at five GHz U-NII band frequencies,
between about 4915 MHz and about 5825 MHz (used for Wi-Fi). In other
mobile devices, the RF signal is at 1575.42 and 1227.60 MHz (used for
GPS). In other mobile devices, the RF signal is at UMTS/LTE band
frequencies, which may be about 800 MHz, about 850 MHz, about 900 MHz,
about 1500 MHz, about 1700 MHz, about 1800 MHz, about 1900 MHz, or about
2100 MHz. Of course, other frequency bands may be supported by the mobile
device. For each frequency band supported by the mobile device, an
antenna must be able to transduce the electromagnetic wave into a voltage
at a specified impedance.

[0004] The mobile device typically has antennas that may be planar or
three-dimensional structures distributed with respect to a device
housing, e.g., embedded within the mechanical structure of the device.
There may be a number of antennas greater than, equal to or less than the
number of wireless frequencies and standards supported by the device. A
set of antennas may be around the perimeter of the device, on the back,
and/or on the front.

[0005] Most materials are not RF transparent and will cause diffraction
effects. One of the challenges with mobile devices is that human body
parts, such as hands and arms, may attenuate the signal produced from a
transmitter and/or may attenuate signals transmitted by other devices,
e.g., due the absorption/redirection of radio frequency signals on the
human body. For example, a hand holding a mobile communication device can
affect transmission and reception of wireless communication signals.

SUMMARY OF THE EMBODIMENTS

[0006] In a first embodiment of the invention there is provided a wireless
communications device having a housing, an RF transceiver disposed in the
housing, a plurality of antennas coupled to the transceiver and
distributed with respect to the housing; and processing circuitry
disposed in the housing and coupled to the RF transceiver. The processing
circuitry is configured to cause the RF transceiver to transmit an RF
reference signal, to determine at least one characteristic of the RF
reference signal reflected back from each of the plurality of antennas,
to store the at least one determined characteristics, and to process the
at least one determined characteristics in order to select at least one
antenna of the plurality of antennas based on the at least one determined
characteristics.

[0007] In a further related embodiment, the processing circuitry is
configured to select a plurality of antennas based on the at least one
characteristic of the reflected signal from each of the plurality of
antennas and to selectively couple the plurality of selected antennas to
the transceiver. Optionally, the communications device includes a
programmable switching device coupled to the plurality of antennas and to
the processing circuitry, wherein the processing circuitry is configured
to selectively couple the plurality of selected antennas to the
transceiver via the programmable switching device. Also optionally, the
processing circuitry is configured to selectively couple the plurality of
selected antennas to the transceiver in parallel via the programmable
switching device.

[0008] In another related embodiment, the device includes a controllable
impedance coupled to the plurality of antennas and to the processing
circuitry, wherein the processing circuitry is configured to selectively
control impedance between the RF transceiver and at least one antenna.

[0009] In yet another related embodiment, the at least one characteristic
includes at least one of amplitude, phase, dispersion, waveform shape, or
distortion.

[0010] In another embodiment, the invention is a method of providing RF
communication using a wireless communications device having an RF
transceiver and a plurality of antennas coupled to the RF transceiver.
The method of this embodiment includes:

[0012] determining at least one characteristic of the RF reference signal
reflected back from each of the plurality of antennas;

[0013] storing the at least one determined characteristics; and

[0014] processing the at least one determined characteristics in order to
select at least one antenna of the plurality of antennas based on the at
least one determined characteristics.

[0015] In a related embodiment, processing the at least one determined
characteristics in order to select at least one antenna of the plurality
of antennas based on the at least one determined characteristics
includes:

[0016] selecting a plurality of antennas based on the at least one
characteristic of the reflected signal from each of the plurality of
antennas; and

[0017] selectively coupling the plurality of selected antennas to the
transceiver.

[0018] As a further option of this related embodiment, selectively
coupling the plurality of selected antennas to the transceiver includes
selectively coupling the plurality of selected antennas to the
transceiver via a programmable switching device. Furthermore, and
optionally, selectively coupling the plurality of selected antennas to
the transceiver via a programmable switching device includes selectively
coupling the plurality of selected antennas to the transceiver in
parallel via the programmable switching device.

[0019] Another related embodiment further includes a controllable
impedance coupled to the plurality of antennas and to the processing
circuitry, wherein the processing circuitry is configured to selectively
control impedance between the RF transceiver and at least one antenna.

[0020] In another related embodiment, the at least one characteristic
includes at least one of amplitude, phase, dispersion, waveform shape, or
distortion.

[0021] In another embodiment, there is provided a wireless communications
device having a housing, an RF transceiver disposed in the housing, a
plurality of antennas coupled to the transceiver and distributed with
respect to the housing, and processing circuitry disposed in the housing
and coupled to the RF transceiver. The processing circuitry is configured
to cause the RF transceiver to transmit an RF reference signal, to
determine at least one characteristic of the RF reference signal
reflected back from each of the plurality of antennas, to store the at
least one determined characteristics, and to process the at least one
determined characteristics in order to control at least one function of
the device.

[0022] In a further related embodiment, the at least one characteristic
includes at least one of amplitude, phase, dispersion, waveform shape, or
distortion. Optionally, the at least one function includes at least one
of selecting at least one antenna to couple to a transceiver, selecting
at least one antenna to decouple from a transceiver, or coupling multiple
antennas to form a larger effective antenna. Optionally, the processing
the at least one determined characteristics in order to control at least
one function includes characterizing at least one aspect of the
environment around the device based on the at least one determined
characteristics; and controlling at least one function of the device
based on the at least one aspect. Optionally, the at least one aspect
includes at least one of, the presence or absence of an object, the
distance of an object from the device, the location of an object relative
to the device, movement of an object relative to the device, orientation
of an object relative to the device, a disposition of the device; or a
time-of-flight measurement of an object to the device.

[0023] In a further related embodiment, the at least one function includes
activating a feature of the device based on such characterization.
Optionally, the feature is activated upon detecting that an object is
approaching the device but before the object contacts the device. Also
optionally, the at least one function includes controlling an application
running in the device based on such characterization. Optionally, the
object includes a body part.

[0024] In another embodiment, the invention provides a method of
controlling at least one function of a wireless communications device
providing RF communication using a wireless device having a plurality of
antennas. The method includes:

[0026] determining at least one characteristic of the RF reference signal
reflected back from each of the plurality of antennas;

[0027] storing the at least one determined characteristics; and

[0028] processing the at least one determined characteristics in order to
control at least one function of the device.

[0029] In a further related embodiment, the at least one characteristic
includes at least one of amplitude, phase, dispersion, waveform shape, or
distortion. Optionally, the at least one function includes at least one
of selecting at least one antenna to couple to a transceiver, selecting
at least one antenna to decouple from a transceiver, or coupling multiple
antennas to form a larger effective antenna. Optionally, the processing
the at least one determined characteristics in order to control at least
one function includes characterizing at least one aspect of the
environment around the device based on the at least one determined
characteristic and controlling at least one function of the device based
on the at least one aspect. Optionally, the at least one aspect includes
at least one of the presence or absence of an object, the distance of an
object from the device, the location of an object relative to the device,
movement of an object relative to the device, orientation of an object
relative to the device, a disposition of the device; or a time-of-flight
measurement of an object to the device. Optionally, the at least one
function includes activating a feature of the device based on such
characterization. Optionally, the feature is activated upon detecting
that an object is approaching the device but before the object contacts
the device. Optionally, the at least one function includes controlling an
application running in the device based on such characterization.
Optionally, wherein the object includes a body part.

[0030] Additional embodiments may be disclosed and claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The foregoing features of embodiments will be more readily
understood by reference to the following detailed description, taken with
reference to the accompanying drawings, in which:

[0032]FIG. 1 schematically shows the front and back sides of a mobile
communications device;

[0033] FIG. 2 schematically shows a hand holding the device of FIG. 1 on
the back of the device;

[0034] FIG. 3 shows an alternative design of an antenna system including N
identical or different antenna elements, in accordance with an exemplary
embodiment;

[0035] FIG. 4 shows the antenna configuration of FIG. 3 when the hand is
present;

[0036] FIG. 5 is a schematic block diagram for circuitry used to implement
the features of FIG. 4, in accordance with an exemplary embodiment;

[0037] FIG. 6 is a logic flow diagram for determining the antenna(s) that
should be selected in FIG. 5, in accordance with an exemplary embodiment;

[0038] FIG. 7 is a schematic block diagram showing circuitry with multiple
antenna elements connected to a switch fabric, in accordance with an
exemplary embodiment;

[0039] FIG. 8 is a schematic block diagram showing a more detailed
circuitry implementation, in accordance with an exemplary embodiment; and

[0040] FIG. 9 is a logic flow diagram for determining the antenna(s) that
should be selected in FIG. 8, in accordance with an exemplary embodiment.

[0041] It should be noted that the foregoing figures and the elements
depicted therein are not necessarily drawn to consistent scale or to any
scale. Unless the context otherwise suggests, like elements are indicated
by like numerals.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Definitions

[0042] As used in this description and the accompanying claims, the
following terms shall have the meanings indicated, unless the context
otherwise requires:

[0043] A "set" has at least one member.

[0044] A "wireless communications device" is a device that has wireless
communication capabilities, such as by Bluetooth, Wi-Fi, GSM (GPRS, 3G,
4G) or CDMA, GPS, RFID, or other wireless communication technology. A
wireless communications device may be virtually any type of device, e.g.,
from mobile devices to anything that could be tagged in the physical
world.

[0046] With regard to a plurality of antennas, the term "distributed with
respect to the housing" means that the antennas are placed at various
locations within the housing and/or on one or more internal or external
surfaces of the housing and/or forming one or more surfaces of the
housing itself (e.g., all or part of a front, back, and/or outer edge of
the housing).

[0047]FIG. 1 schematically shows the front and back sides of an exemplary
mobile communications device 100. The mobile device communicates
wirelessly with various types of devices, such as base stations,
satellites and other wireless devices, using any of a number of wireless
protocols using electromagnetic waves as RF signals. In some mobile
devices, the RF signal is at ISM-band frequencies, between about 2.400
GHz and about 2.483 GHz (used for IEEE 802.11 Wi-Fi and Bluetooth). In
other mobile devices, the RF signal is transmitted at five GHz U-NII band
frequencies, between about 4915 MHz and about 5825 MHz (used for Wi-Fi).
In other mobile devices, the RF signal is at 1575.42 and 1227.60 MHz
(used for GPS). In other mobile devices, the RF signal is at UMTS/LTE
band frequencies, which may be about 800 MHz, about 850 MHz, about 900
MHz, about 1500 MHz, about 1700 MHz, about 1800 MHz, about 1900 MHz, or
about 2100 MHz. Of course, other frequency bands may be supported by the
mobile device. For each frequency band supported by the mobile device, an
antenna must be able to transduce the electromagnetic wave into a voltage
at a specified impedance. The mobile device typically has antennas that
may be planar or three-dimensional structures distributed with respect to
a device housing, e.g., embedded within the mechanical structure of the
device. There may be a number of antennas greater than, equal to or less
than the number of wireless frequencies and standards supported by the
device. A set of antennas may be around the perimeter of the device 100,
on the back 120, and/or on the front. It should be noted that antenna 120
is simply a bounding box of a set of geometric patterns that define the
set of antennas.

[0048] In this exemplary embodiment, an auxiliary antenna 105 is shown to
interface the mobile device with one or more RFID tags 130 via a radio
frequency field 125 at 840-960 MHz, or in principle other RF/microwave
bands, such as 2.400-2.483 GHz. If the 2.400-2.483 GHz band is not
available for RFID operation, the auxiliary antenna 105 may be needed.
The primary purpose of the mobile device is for all communication other
than the RFID function; therefore, the antennas 120 will occupy the
largest area or volume of the accessible area of the device. Antenna 105
may not be the ideal geometry given the wavelength of interaction for
RFID (typically 12-35 cm), but nevertheless, given a constrained geometry
of a mobile phone, the compromise may be necessary.

[0049] Most materials are not RF transparent and will cause diffraction
effects. One of the challenges with mobile devices is that human body
parts, such as hands and arms, may attenuate the signal produced from a
transmitter and/or may attenuate signals transmitted by other devices,
e.g., due the absorption/redirection of radio frequency signals on the
human body. For example, a hand holding a mobile communication device can
affect transmission and reception of wireless communication signals.

[0050] FIG. 2 schematically depicts a hand 200 holding a device on the
back of the device 210. In this case, the finger and proximity of the
hand means the RFID antenna 105 is either poorly matched now and/or
cannot radiate properly. In the state of the art, RFID reader circuitry
incorporates self-jammer cancellation, return loss matching, or other
means of improving the noise floor or dynamic range of the receiver. This
may address the poor antenna match, but cannot address the diminished
antenna radiation pattern. In the ideal case of RFID operation, at the
point the RFID tag transitions from being powered to not-powered, termed
the power up threshold, the receiver of an RFID reader still possesses
sufficient receive margin to decode packets with very low probability of
error, or packet error rate (PER). This is termed transmitter-limited. In
the case where the receiver is the limiting factor, not the RFID tag,
this is termed receiver-limited. As RFID tags 130 are powered by the RFID
field 225, the hand blocking the RFID antenna 105 may diminish the tag
read and write range to the extent that the tags may not power up in the
manipulatory range 227. Note the data, location and voice-communication
antennas 120 may also be subject to this change in antenna
characteristics, but since the operational path loss for wireless data,
location and voice communications is greater (90-150 dB) than RFID path
loss (40-60 dB), the link margin in the presence of the hand usually
remains positive. Therefore, the RFID communications system has two
disadvantages to contend with in the incorporation of mobile phones
relative to conventional data, location, and voice communications: a low
link margin, and a sub-optimal antenna design on the mobile
communications device.

[0051] In certain embodiments of the present invention, a wireless
communications device includes multiple switchable antenna elements that
may be used to improve interfacing of the wireless communications device
with other devices, such as for interfacing of an RFID-equipped mobile
communications device with other RFID devices (e.g., to better ensure
power delivery to and/or communication with such other RFID devices)
and/or may be used to characterize various aspects of the environment
around the wireless communications device, such as to help create a more
natural interface for allowing people to interact with the wireless
communications device.

[0052] FIG. 3 shows an alternative design of an antenna system 300,
including N identical or different antenna elements (310 for example), in
accordance with one exemplary embodiment. These elements may exist in one
embodiment exemplary as etched or printed elements on a printed or
flexible circuit board, although the present invention is not limited to
etched or printed antenna elements and instead can include one or more
other types of antennas. The antennas may be virtually any shape, size,
thickness, or placement. For example, using 3D printing or conventional
machining technology, these elements may be three-dimensional metal
structures. Each element may possess an independent path to the
transmitter, or if configured for full flexibility, additionally or
alternatively may allow a voltage, ground, resistive and/or reactive
connection to neighboring elements to allow a larger antenna to be
formed. The size, number and shape of the elements shown in FIG. 3 are
only a suggestion of the design. The original far field antennas for data
and voice communications 120 may also be included among the antenna
elements, e.g., using M smaller antennas arranged in a periodic or
aperiodic lattice. Thus, for example, antenna elements may be included
for ISM-band frequencies between about 2.400 GHz and about 2.483 GHz
(used for Wi-Fi and Bluetooth), for 5 GHz U-NII band frequencies between
about 4915 MHz and about 5825 MHz (used for Wi-Fi), for 1575.42 and
1227.60 MHz band frequencies (used for GPS), for UMTS/LTE band
frequencies (which may be about 800 MHz, about 850 MHz, about 900 MHz,
about 1500 MHz, about 1700 MHz, about 1800 MHz, about 1900 MHz, or about
2100 MHz), for 840-960 MHz band frequencies (used for RFID), and/or for
other RF/microwave bands. It should be noted that although this diagram
shows the antenna elements as visible on the surface of the mobile
communication device, this is for illustrative purposes and the antenna
elements may not be visible, e.g., hidden under glass, plastic, ceramic,
composite or other material.

[0053] FIG. 4 shows the same antenna configuration 310 when the hand 200
is present. Although many antenna elements are covered on the back of the
device by the hand 205, depicted as darkened elements, several antenna
elements remain uncovered and can be connected to the transmitter
independently of the poor return loss and radiating paths coupled to the
hand. One example of an antenna element that is not impacted by the
presence of the hand is 315. In certain embodiments, some or all of the
free antenna elements may be connected in parallel to the transmitter
and/or receiver of one or more radios. In other embodiments where a radio
protocol has greater than one transmitter and/or receiver, free elements
may be independently connected to each transmitter and receiver. In still
other embodiments, some or all of the free antenna elements may be
connected to each other to optimize radiation and power transfer. With
regard to a mobile communications device with RFID communication
capabilities as discussed with reference to FIGS. 1-2, utilizing the free
antenna elements 315 unburdened by being connected to loaded antenna
elements, it is assumed the RF field produced by the mobile
communications device 325 will be greater in magnitude to the traditional
design 105 shown in FIG. 2, but may be not as large as the RF field 125
when the hand is not present as shown in FIG. 1. If the RF field 325 is
larger than the RF field 225, the read range 427 should be larger than
227, making the manipulatory space more reliable. It should be noted that
this embodiment may be generalized such that the RFID tag 130 is another
wireless communications device, and that antenna 320 could be composed of
a plurality of antenna elements such as 310, 315.

[0054] FIG. 5 is a schematic block diagram for circuitry used to implement
the features of FIG. 4, in accordance with an exemplary embodiment. As in
a conventional RFID reader, a directional coupler 505 couples transmitter
power to the OUT port; the directional coupler is coupled to one of N
antenna ports 510-512 through a digitally controllable switch 500
controlled by digital signals 501. In some embodiments, the directional
coupler 505 could be a circulator, and the COUP port would not be
present. In this example, three of the N antennas 530-532 are
highlighted. The ISO port of the directional coupler carries the power
from the antennas that goes into the OUT port and directs this to the
receiver. This includes the self-jammer from the transmitter and the RFID
tag backscatter data, and the transmit power at the IN port that is
reduced by the directional coupler isolation (typically 15-40 dB). The
self-jammer level is a function of the transmit power level and the
return loss of the antenna. The RFID tag backscatter data level is a
function of the path loss to the RFID tag and the RFID tag itself. The
COUP port contains the transmit power reduced by the coupling factor
(typically 3-20 dB) and the antenna RF signal reduced by the directional
coupler isolation (typically 15-40 dB). The coupled power, like the
self-jammer level is a function of the transmit power. The antennas
510-512 shown have their corresponding bounding box antenna elements on
the mobile device 530-532 with the hand 200, 205. In this embodiment, due
to the N-way switch 500, only a single antenna element may be active at a
time. However, by applying time-sequenced digital controls 501, the
antenna patterns may use multiple antenna elements appropriately.

[0055] FIG. 6 is a logic flow diagram for determining the antenna(s) that
should be selected in FIG. 5, in accordance with an exemplary embodiment.
At the start of the algorithm, the digital switch 500 is configured to
switch position 1 601. If the analog switch can be damaged with the RF
power on, the transmitter is optionally turned on to power P 602. This
power may be lower than the final transmitter power, in order to save
power. Measurements on the ISO and COUP ports are made on the directional
coupler 505. The ISO port measures the RX signal, while the COUP port
measures the TX signal. The pair of TX (power or I&Q signal) and RX
(power or I&Q signal) may be stored as a vector. The transmitter is then
optionally turned off 605, and the counter i is incremented 606. If the
value of i is less than N 607, the antenna is switched to this new
setting 609, and optionally the power is turned on to power P 610, then
the cycle is repeated again 603. If i is equal to N 607, the antenna
switch 500 is configured to choose the antenna with the lowest combined
TX and RX vector norm or highest return loss in dB. In the case where the
switch 500 allows multiple antennas to be connected together in parallel
(corresponding loads may be present as well), two or more of the top M
antennas (M<N) that have the lowest combined TX and RX vector norm or
highest return loss in dB may be connected in parallel. If the top M
elements cannot be connected together, the elements may be switched in a
time-sequenced manner.

[0056] FIG. 7 is a schematic block diagram showing circuitry with multiple
antenna elements 710-712 connected to a switch fabric 700, in accordance
with an exemplary embodiment. This fabric may allow neighboring antenna
elements to be connected together to enable a larger antenna and/or may
allow multiple non-neighboring antennas to be connected together. A
controllable impedance 720 may be added to the COUP port of the
directional coupler to allow energy to be maximally transferred from the
transmitter, and for energy to be transmitted into the receiver (e.g.,
when the resulting antenna structure does not possess an impedance that
matches the impedance of the transmit power amplifier (PA) 502 and
directional coupler 505).

[0057] FIG. 8 is a schematic block diagram showing a more detailed
circuitry implementation, in accordance with an exemplary embodiment. The
switch matrix is implemented as N-independent switches where antennas
510-512 may be connected in parallel. The controllable impedance is
implemented as an impedance control circuit, for example an impedance
control circuit as described in United States Published Patent
Application No. US 2010/0069011, which is hereby incorporated herein by
reference. A quadrature hybrid element 820 is similar to a directional
coupler, except the coupling between the IN and OUT and the IN and COUP
ports are equal and with a value of -3 dB. The phase relationship between
the OUT and COUP ports is 90 degrees out of phase. On the OUT and COUP
ports, variable capacitances 830-831 and variable resistance 835 on the
ISO port allow one to create a range of complex impedances in one half of
a Smith Chart. The open and short switch 840, allows one to flip location
of the impedance to the other half of the Smith Chart.

[0058] FIG. 9 is a logic flow diagram for determining the antenna(s) that
should be selected in FIG. 8, in accordance with an exemplary embodiment.
At the start of the algorithm, the digital switch is configured 500 to
switch position 1 901. If the analog switch can be damaged with the RF
power on, the transmitter is optionally turned on to power P 902. This
power may be lower than the final transmitter power, in order to save
power. Measurements on the ISO and COUP ports are made on the directional
coupler 505 at step 903. The ISO port measures the RX signal, while the
COUP port measures the TX signal. The pair of TX (power or I&Q signal)
and RX (power or I&Q signal) may be stored as a vector. The transmitter
is then optionally turned off 905, and the counter i is incremented 906.
If the value of i is less than N 907, the antenna is switched to this new
setting 909, and optionally the power is turned on to power P 910, then
the cycles is repeated again 903. If i is equal to N 907, the antenna
switch 500 is configured to choose the antenna with the lowest combined
LO and RX vector norm or highest return loss in dB 908. The variable
impedance match 720 connected to the COUP port, such as that in FIG. 8 is
changed to match the impedance to the connected antennas. In the case
where the switch 500 allows multiple antennas to be connected together in
parallel (corresponding loads may be present as well), the top M antennas
(M<N) that have the lowest combined LO and RX vector norm or highest
return loss in dB are selected. If the top M elements cannot be connected
together, the switch elements may be switched in a time-sequenced manner.

[0059] In accordance with various alternative embodiments, multiple
antenna elements and related circuitry and logic flows of the type
discussed above can be used to characterize various aspects of the
environment around the wireless communications device (referred to herein
for convenience as proximity detection). Specifically, due to the fact
that a portion of the transmitted RF signal may be reflected by an object
back through the directional coupler (e.g., 505 in FIG. 5) into the
receiver and a potential separate return path, the reflected energy can
be characterized to detect such things as, for example, the presence or
absence of an object (e.g., a person's hand or arm), the type of object
(e.g., a metallic object vs. a body part), the distance of the object
from the device, the location of the object relative to the device (e.g.,
whether the object at a front, back, or side of the device), movement of
the object relative to the device (e.g., toward or away from the device
and/or other movements), orientation of the object, etc. Thus, for
example, processing circuitry in the device may transmit an RF reference
signal, determine at least one characteristic of the RF reference signal
reflected back from each of the plurality of antennas, and process the
determined characteristics in order to control at least one function of
the device (which may include control of an application running in the
device). The RF reference signal may be constant (e.g., a single
frequency) or may be variable (e.g., a sequence of different
frequencies). The characteristic(s) can include such things as amplitude,
vector, phase, dispersion, and/or shape or distortion of waveform of
transmitted signal.

[0060] As but one example of a potential use for such proximity detection,
a user interface for a device may utilize proximity information generated
from such proximity detection to allow a user to control features of a
device or application. As shown in FIGS. 4 and 5, the elements covered,
for example 533, will show diminished return loss compared to the
elements which are not covered, for example 530-532. This information may
be used, for example, to detect the approach of a person to begin a user
interface interaction even before the user makes physical contact with
the device, thereby creating the impression of a magical experience for a
user. The range at which return loss variations could be detected could
be as small as contact with the mobile device, to several millimeters, to
several tens of centimeters. The processing circuitry in the device may
be implemented such that a significant increase in the backscatter signal
without a tag response may indicate the presence of an object such as a
hand or local body part. That is, the shielded antenna elements may be
used for object detection. The shielded antenna elements may also be used
to image the orientation of the object. The unshielded antenna elements
may be used, for example, to interface with RFID tags or other
backscatter devices. For example, currently, phones often will receive
email updates by push methods, where a network socket is open and data
from email providers is sent as soon as new email arrives into the
account. Some email accounts receive email by checking email servers on
some preset interval. These methods can appreciably drain a battery of a
mobile device throughout the day. By being able to detect the human body
approaching a device, it may provide sufficient time to wake up a device,
connect to an email service, and start downloading email to the device,
so that as soon as the user had logged into their device, the email
appears ready. In other uses, proximity detection could be used
quantitatively for interactivity (e.g., such as gaming or music
creation), could be used to determine the disposition of the device
(e.g., such as whether the device is being held, is placed in a holster,
or is placed on a table, e.g., by virtue of different reflective
characteristics of the different materials), could be used for security
purposes (e.g., to verify that two communicating devices are near one
another, or to verify that a person is present for a transaction), or
could be used for other proximity-based functions.

[0061] In making a user interface that will separate manipulatory and
ambulatory space for a mobile device interfacing with one or more RFID
tags or other wireless devices, a time-of-flight-based measurement may be
used to obtain an accurate separation of manipulatory and ambulatory
space. For example, processing circuitry in the device can measure the
time between transmitting an RF reference signal and receiving reflected
energy at one or more of the antenna elements. Based on such time-based
information, the device can determine, for example, the distance and/or
location of an object relative to the device (e.g., if the reflection is
received sooner at a first antenna element compared to a second antenna
element--sometimes referred to as time-difference of arrival--then the
object is likely to be closer to the first antenna element.

[0062] It should be noted that arrows may be used in drawings to represent
communication, transfer, or other activity involving two or more
entities. Double-ended arrows generally indicate that activity may occur
in both directions (e.g., a command/request in one direction with a
corresponding reply back in the other direction, or peer-to-peer
communications initiated by either entity), although in some situations,
activity may not necessarily occur in both directions. Single-ended
arrows generally indicate activity exclusively or predominantly in one
direction, although it should be noted that, in certain situations, such
directional activity actually may involve activities in both directions
(e.g., a message from a sender to a receiver and an acknowledgement back
from the receiver to the sender, or establishment of a connection prior
to a transfer and termination of the connection following the transfer).
Thus, the type of arrow used in a particular drawing to represent a
particular activity is exemplary and should not be seen as limiting.

[0063] It should be noted that headings are used above for convenience and
are not to be construed as limiting the present invention in any way.

[0064] It should be noted that terms such as "client," "server," "switch,"
and "node" may be used herein to describe devices that may be used in
certain embodiments of the present invention and should not be construed
to limit the present invention to any particular device type unless the
context otherwise requires. Thus, a device may include, without
limitation, a bridge, router, bridge-router (brouter), switch, node,
server, computer, appliance, or other type of device. Such devices
typically include one or more network interfaces for communicating over a
communication network and a processor (e.g., a microprocessor with memory
and other peripherals and/or application-specific hardware) configured
accordingly to perform device functions. Communication networks generally
may include public and/or private networks; may include local-area,
wide-area, metropolitan-area, storage, and/or other types of networks;
and may employ communication technologies including, but in no way
limited to, analog technologies, digital technologies, optical
technologies, wireless technologies (e.g., Bluetooth), networking
technologies, and internetworking technologies.

[0065] It should also be noted that devices may use communication
protocols and messages (e.g., messages created, transmitted, received,
stored, and/or processed by the device), and such messages may be
conveyed by a communication network or medium. Unless the context
otherwise requires, the present invention should not be construed as
being limited to any particular communication message type, communication
message format, or communication protocol. Thus, a communication message
generally may include, without limitation, a frame, packet, datagram,
user datagram, cell, or other type of communication message. Unless the
context requires otherwise, references to specific communication
protocols are exemplary, and it should be understood that alternative
embodiments may, as appropriate, employ variations of such communication
protocols (e.g., modifications or extensions of the protocol that may be
made from time-to-time) or other protocols either known or developed in
the future.

[0066] It should also be noted that logic flows may be described herein to
demonstrate various aspects of the invention, and should not be construed
to limit the present invention to any particular logic flow or logic
implementation. The described logic may be partitioned into different
logic blocks (e.g., programs, modules, functions, or subroutines) without
changing the overall results or otherwise departing from the true scope
of the invention. Often times, logic elements may be added, modified,
omitted, performed in a different order, or implemented using different
logic constructs (e.g., logic gates, looping primitives, conditional
logic, and other logic constructs) without changing the overall results
or otherwise departing from the true scope of the invention.

[0067] The present invention may be embodied in many different forms,
including, but in no way limited to, computer program logic for use with
a processor (e.g., a microprocessor, microcontroller, digital signal
processor, or general purpose computer), programmable logic for use with
a programmable logic device (e.g., a Field Programmable Gate Array (FPGA)
or other PLD), discrete components, integrated circuitry (e.g., an
Application Specific Integrated Circuit (ASIC)), or any other means
including any combination thereof. Computer program logic implementing
some or all of the described functionality is typically implemented as a
set of computer program instructions that is converted into a computer
executable form, stored as such in a computer readable medium, and
executed by a microprocessor under the control of an operating system.
Hardware-based logic implementing some or all of the described
functionality may be implemented using one or more appropriately
configured FPGAs.

[0068] Computer program logic implementing all or part of the
functionality previously described herein may be embodied in various
forms, including, but in no way limited to, a source code form, a
computer executable form, and various intermediate forms (e.g., forms
generated by an assembler, compiler, linker, or locator). Source code may
include a series of computer program instructions implemented in any of
various programming languages (e.g., an object code, an assembly
language, or a high-level language such as Fortran, C, C++, JAVA, or
HTML) for use with various operating systems or operating environments.
The source code may define and use various data structures and
communication messages. The source code may be in a computer executable
form (e.g., via an interpreter), or the source code may be converted
(e.g., via a translator, assembler, or compiler) into a computer
executable form.

[0069] Computer program logic implementing all or part of the
functionality previously described herein may be executed at different
times on a single processor (e.g., concurrently) or may be executed at
the same or different times on multiple processors and may run under a
single operating system process/thread or under different operating
system processes/threads. Thus, the term "computer process" refers
generally to the execution of a set of computer program instructions
regardless of whether different computer processes are executed on the
same or different processors and regardless of whether different computer
processes run under the same operating system process/thread or different
operating system processes/threads.

[0070] The computer program may be fixed in any form (e.g., source code
form, computer executable form, or an intermediate form) either
permanently or transitorily in a tangible storage medium, such as a
semiconductor memory device (e.g., a RAM, ROM, PROM, EEPROM, or
Flash-Programmable RAM), a magnetic memory device (e.g., a diskette or
fixed disk), an optical memory device (e.g., a CD-ROM), a PC card (e.g.,
PCMCIA card), or other memory device. The computer program may be fixed
in any form in a signal that is transmittable to a computer using any of
various communication technologies, including, but in no way limited to,
analog technologies, digital technologies, optical technologies, wireless
technologies (e.g., Bluetooth), networking technologies, and
internetworking technologies. The computer program may be distributed in
any form as a removable storage medium with accompanying printed or
electronic documentation (e.g., shrink wrapped software), preloaded with
a computer system (e.g., on system ROM or fixed disk), or distributed
from a server or electronic bulletin board over the communication system
(e.g., the Internet or World Wide Web).

[0071] Hardware logic (including programmable logic for use with a
programmable logic device) implementing all or part of the functionality
previously described herein may be designed using traditional manual
methods, or may be designed, captured, simulated, or documented
electronically using various tools, such as Computer Aided Design (CAD),
a hardware description language (e.g., VHDL or AHDL), or a PLD
programming language (e.g., PALASM, ABEL, or CUPL).

[0072] Programmable logic may be fixed either permanently or transitorily
in a tangible storage medium, such as a semiconductor memory device
(e.g., a RAM, ROM, PROM, EEPROM, or Flash-Programmable RAM), a magnetic
memory device (e.g., a diskette or fixed disk), an optical memory device
(e.g., a CD-ROM), or other memory device. The programmable logic may be
fixed in a signal that is transmittable to a computer using any of
various communication technologies, including, but in no way limited to,
analog technologies, digital technologies, optical technologies, wireless
technologies (e.g., Bluetooth), networking technologies, and
internetworking technologies. The programmable logic may be distributed
as a removable storage medium with accompanying printed or electronic
documentation (e.g., shrink wrapped software), preloaded with a computer
system (e.g., on system ROM or fixed disk), or distributed from a server
or electronic bulletin board over the communication system (e.g., the
Internet or World Wide Web). Of course, some embodiments of the invention
may be implemented as a combination of both software (e.g., a computer
program product) and hardware. Still other embodiments of the invention
are implemented as entirely hardware, or entirely software.

[0073] Various embodiments of the present invention may be characterized
by the potential claims listed in the paragraphs following this paragraph
(and before the actual claims provided at the end of this application).
These potential claims form a part of the written description of this
application. Accordingly, subject matter of the following potential
claims may be presented as actual claims in later proceedings involving
this application or any application claiming priority based on this
application.

[0074] Without limitation, potential subject matter that may be claimed
(prefaced with the letter "P" so as to avoid confusion with the actual
claims presented below) includes:

[0075] P1. A method of controlling a wireless device having a plurality of
antennas, the method comprising: [0076] at the wireless device,
transmitting an RF signal; [0077] receiving a portion of the transmitted
RF signal reflected by the object by each of the antennas; [0078]
determining the proximity of the object to the wireless device based on a
signal strength of the received signal; and [0079] controlling the
wireless device based on the proximity of the object.

[0080] P2. A method of detecting orientation of an object using a wireless
device having a plurality of antennas, the method comprising: [0081] at
the wireless device, receiving signals from each of the plurality of
antennas; [0082] determining a signal level of each of the signals; and
[0083] determining the orientation of the object based on the relative
signal levels of the signals.

[0084] P3. A method according to claim P2, wherein determining the
orientation of the object based on the relative signal levels of each of
the signals comprises: [0085] shielding at least one of the antennas
based on the relative signal levels; and [0086] determining the
orientation based on at least one of a pattern of shielded antennas or a
pattern of unshielded antennas.

[0087] P4. A mobile phone including an RFID reader.

[0088] P5. A mobile phone according to claim P4, further comprising at
least one auxiliary antenna coupled to the RFID reader.

[0089] The present invention may be embodied in other specific forms
without departing from the true scope of the invention, and numerous
variations and modifications will be apparent to those skilled in the art
based on the teachings herein. Any references to the "invention" are
intended to refer to exemplary embodiments of the invention and should
not be construed to refer to all embodiments of the invention unless the
context otherwise requires. The described embodiments are to be
considered in all respects only as illustrative and not restrictive.

Patent applications by Yael G. Maguire, Boston, MA US

Patent applications in class TRANSMITTER AND RECEIVER AT SAME STATION (E.G., TRANSCEIVER)

Patent applications in all subclasses TRANSMITTER AND RECEIVER AT SAME STATION (E.G., TRANSCEIVER)